1. Field of Invention
The present invention relates to a lighting unit and a projector including the same.
2. Description of Related Art
FIG. 5 is a schematic showing a lighting unit which contains a reflector formed from an ellipsoidal mirror (hereinafter “ellipsoid reflector”). As described in JP-A-2000-347293 (FIG. 1), for example, the lighting unit of this type includes: a light source lamp 10 having a light emitting tube 10B for emitting illumination light and an ellipsoid reflector 10A for reflecting the illumination light emitted from the light emitting tube 10B; and a parallelizing lens 16 for parallelizing the illumination light reflected by the ellipsoid reflector 10A of the light source lamp 10. In the figure, reference numerals 20 and 30 denote a pair of lens arrays, and a reference numeral 40 denotes a polarizing conversion element, respectively.
According to this related art lighting unit, the illumination light emitted from the light emitting tube 10B is reflected by the ellipsoid reflector 10A and then converted into almost parallel light by the parallelizing lens 16. In related art the lighting unit, the outside diameter of the light flux released from the parallelizing lens 16 can be made smaller than the outside diameter of the ellipsoid reflector, allowing the subsequent optical system to be made compact. Thus, the related art lighting unit of this type meets recent demand for miniaturization of projectors, which is significant in view of current situation where further miniaturization of a light source lamp is difficult because of the difficulty in miniaturization of a light emitting tube.
In recent years, there has been also increasing demand for thinner projectors as well as small-sized ones.